2.5 Properties of Water, Solutions, and pH

Question 1

properties of water

Answer 1

1. cohesion and adhesion
2. solvent of life
3. less dense as a solid
4. high specific heat
5. high heat of vaporization

Question 2

cohesion

Answer 2

H bonding between water molecules

Question 3

adhesion

Answer 3

H bonding between water and other substances

Question 4

solvent

Answer 4

solvents dissolve solutes, creating solutions

Question 5

specific heat

Answer 5

the amount of energy required to heat up 1 gram of a substance by 1 degree Celsius

Question 6

heat of vaporization

Answer 6

the amount of energy required for 1 gram of water to evaporate

Question 7

how does water’s polarity give it the property of cohesion and adhesion

Answer 7

water’s polarity gives it the ability to form hydrogen bonds with other water molecules and other substances

Question 8

how does water’s polarity give it the property of being a good solvent

Answer 8

water’s polarity allows it to dissolve hydrophilic substances (polar and ionic substances. fats and lipids are hydrophobic and don’t dissolve in water.

Question 9

how does water’s polarity give it the property of being less dense as a solid than a liquid

Answer 9

when frozen, hydrogen bonds stabilize, which leaves more space between water molecules than when they are in liquid form. this extra space is what causes ice to be less dense than liquid water

Question 10

how does water’s polarity give it the property of having a high heat of vaporization

Answer 10

to become water vapor, the hydrogen bonds must be fully broken. hydrogen bonds are strong, and thus difficult to break.

Question 11

why is the property of cohesion and adhesion important to life

Answer 11

it allows plants to pull water against the force of gravity and creates surface tension

Question 12

why is the property of being a good solvent important to life

Answer 12

transportation within the bloodstream requires substances to be dissolved

Question 13

why is the property of being less dense as a solid than a liquid important to life

Answer 13

ice floats, ice insulates water below, bodies of water don’t freeze over, seasonal turnover (when ice melts, cold water sinks down and cycles nutrients)

Question 14

why is the property of having a high specific heat important to life

Answer 14

being near water stabilizes temperature

Question 15

why is the property of having a high heat of vaporization important to life

Answer 15

evaporative cooling (organisms rely on heat of vaporization to remove body heat)

Question 16

concentration

Answer 16

the amount of solute per volume of a solution

Question 17

pH

Answer 17

potential hydrogen
-log[H30+]

Question 18

pOH

Answer 18

potential hydroxide
-log[OH-]

Question 19

hydroxide

Answer 19

OH-

Question 20

hydronium

Answer 20

H3O+

Question 21

acid

Answer 21

[H3O+] > [OH-]
pH < 7

Question 22

base

Answer 22

[H3O+] < [OH-]
pH > 7

Question 23

pH = 8

Answer 23

pOH = 6
[H3O+] = 10^-8
[OH-} = 10^-6
base

Question 24

pOH = 11

Answer 24

pH = 3
[H3O+] = 10^-3
[OH-] = 10^-11
acid

Question 25

[H3O+] = 10^-5

Answer 25

pH = 5
pOH = 9
[OH-] = 10^-9
acid

Question 26

[OH-] = 10^-7

Answer 26

pH = 7
pOH = 7
[H3O+] = 10^-7
neutral

Question 27

Compare the concentrations of [H3O+] and [OH-] of two solutions
pH 4 and pH 10

Answer 27

[H3O+]
pH 4 is 10^6 times higher than pH 10
[OH-]
pH 4 is 10^6 times lower than pH 10

Question 28

Compare the concentrations of [H3O+] and [OH-]
pH 8 and pH 6

Answer 28

[H3O+]
pH 8 is 10^2 times lower than pH 6
[OH-]
pH 8 is 10^2 times higher than pH 6